Formaldehyde hydrocarbons

Chemical compounds manufactured at petrochemical plants include methanol, formaldehyde, and halogenated hydrocarbons. Formaldehyde is used in the manufacture of plastic resins, including phenolic, urea, and melamine resins. Halogenated hydrocarbons are used in the manufacture of silicone, solvents, refrigerants, and degreasing agents. 

Oxygenated Hydrocarbons Formaldehyde Acetaldehyde Methanol Ethanol Ethylene oxide Ketene... 

However, the above N0x/03 chemistry is enhanced by the impact of reactive hydrocarbons, formaldehyde and other reactive species. For example, in the case of generic, reactive hydrocarbon, RH, the following reaction se-... 

This scaling law, Eq. (9-48), implies that all components of the stress tensor are linear in the shear rate. Consider for example, a constant-shear-rate experiment. At steady state, not only is the shear stress predicted to be proportional to the shear rate, but so also is the first normal stress difference N This prediction has been nicely confirmed in recent experiments by Takahashi et al. (1994), who studied mixtures of silicon oil and hydrocarbon-formaldehyde resin. Both these fluids are Newtonian, and have the same viscosity, around 10 Pa s. Figure 9-18 shows that both the shear stress o and the first normal stress difference N = shear rate, so that the shear viscosity rj = aly and the so-called normal viscosity rjn = N /y are constants. The first normal stress difference in this mixture must be attributed entirely to the presence of interfaces, since the individual liquids in the mixture have no measurable normal stresses. A portion of the shear stress also comes from the interfacial stress. Figure 9-19 shows that the shear and normal viscosities are both maximized at a component ratio of roughly 50 50. At this component ratio, the interfacial term accounts for roughly half the total shear stress. 

Figure 9.18 Shear-rate dependence of the shear stress ( ), first normal stress difference (Q), shear viscosity (A), and normal viscosity (A) for a 1 1 mixture (by weight) of polydimethylsiloxane (viscosity = 9.74 Pa-s), and Genelite 4050S (hydrocarbon-formaldehyde resin with viscosity =10.1 Pa-s), at25°C. (From Takahashi et al. 1994, with permission ftom the Journal of Rheology.)...

A number of these experiments at 800 torr and 75 mA using a Co—Zr catalyst showed that in the temperature range above 190 °C the catalytic reaction produced chiefly methane (Table 9) and to some extent liquid products — ethanol, hydrocarbons, formaldehyde and water — collected in a trap at 195 K. A partial... 

Impurities that adsorb mito the electrocatalysts surface inhibit the charge-transfer processes, resulting in performance loss. Common fuel impurities include carbon monoxide, ammonia, hydrogen sulfide, hydrogen cyanide, hydrocarbons, formaldehyde, and formic acid [93]. On the cathode side, ambient air may contain impurities such as sulfur dioxide, nitrogen oxides, and particulate matter (including salts) that can affect fuel cell performance [93]. 

Other HR modifying methods and agents are known. Thus, aromatic HRs can react with aldehydes due to the reactive CHj groups they contain. Colored resins with fulvenic structure are formed [189). Aldehyde treated inden-couma-ronic fractions, in the presence of acid or basic catalysts, can form mixed resins wherein inden-coumaronic structures coexist with sequences specific for hydrocarbon-formaldehydic resins [253]. 

When methane and oxygen are converted in the gas phase at temperatures between 850 and 1150 K, C2 hydrocarbons are formed besides carbon monoxide along with minor amounts of C3 j hydrocarbons, formaldehyde, methanol and carbon dioxide. The selectivities depend on the conditions applied i.e., partial pressures of methane and oxygen respectively, as well as temperature. 

Polynuclear aromatic hydrocarbons Formaldehyde—sulfuric acid Various colors on white background... 

Numerous method of producing formaldehyde li y the oxidation of hydrocarbon gases have I>een patented, and increasing amounts of foinialdehyde are made by processes of this type. In this connection, Homer observes that hydrocarbon formaldehyde is usualh obtained from the scrubbers as dilute solution which is not capable of being concentinted economically. It is also stated that it is difficult to olitain formaldehyde free from other... 

Reactions of formaldehyde with aromatic hydrocarbons are similar in cane respects to those involving olefins and may involve a somewhat similar mechanism. However, reactions apparently proceed further than in the ca of olefins, and the simple addition products of methylene ycol or sahstituted methylene glycol have not been isolated. With aromatic hydrocarbons, formaldehyde and hydrogen halides, the primary reaction products isolated are compounds in which one or two halomethyl groups are substituted for hydrogen on the aromatic nucleus. On further reaction, compounds are obtained in which two or more aromatic nuclei are linked together by methylene gi oups. When sulfuric acid is employed as a reaction catalyst, methylene derivatives of this latter type are apparently the pi incipal products obtained. 

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